The present invention relates to an immersion cooling system for cooling electronic sections included in a data processor or similar electronic apparatus by immersing them in a liquid coolant. More particularly, the present invention is concerned with a liquid coolant circulation control system for minimizing the required feed pressure and maintaining the flow rate of a liquid coolant constant while the coolant is circulated.
An immersion cooling system mentioned above is disclosed in, for example, U.S. Pat. No. 4,590,538. This U.S.P. discloses an immersion cooling system having a hollow cylindrical tank storing an inert inquid coolant therein. A plurality of frames are arranged radially in the tank and support a plurality of electronic circuit modules in a stack configuration. A plurality of coolant feeding members and a plurality of coolant collecting members are supported by nearby frames while alternating with each other. These members form passages for the coolant. A plurality of pumps cause the coolant to circulate. A plurality of heat exchangers cool the coolant having been heated by causing it to release heat. This type of conventional immersion cooling system has some problems left unsolved, as follows.
To begin with, each pump has to feed the coolant under a pressure high enough to overcome losses ascribable to the resistance of the heat exchangers, tank and so forth to the flow of the coolant. As a result, the pressure acting on the coolant itself increases, which raise the boiling point of the coolant in the tank, thereby suppressing nuclear boiling cooling.
Another problem is that the tank and other members defining the liquid passages have to be provided with high resistivity to pressure since the pressure acting on the passages increases.